Hey Trond- I've made some progress getting RPC-with-TLS working in the Linux NFS client, but I recently hit an interesting snag and could use a little advice. The software kTLS infrastructure uses do_tcp_sendpages() under the covers, and that function is clearing SOCKWQ_ASYNC_NOSPACE from under xs_nospace(). That prevents xs_run_error_worker() from waking up xprt->sending, stalling an RPC transport waiting for more socket write space. I'm not sure how to address this, and I'm interested in your opinion. For example, why check that flag rather than just waking up xprt->sending unconditionally? Also just for my own understanding of how the write_space mechanism is supposed to work for RPC, I instrumented the code that bumps and decrements sk_write_pending, and found that under normal workloads, the value of that field goes negative and stays there. I'm not sure that's intended...? -- Chuck Lever
